//
// Created by zhangrongxiang on 2017/10/20 10:53
// File client
//

#include <netinet/in.h>
#include <sys/socket.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/epoll.h>
#include <time.h>
#include <unistd.h>
#include <sys/types.h>
#include <arpa/inet.h>

#define MAXSIZE     1024
#define IPADDRESS   "127.0.0.1"
#define SERV_PORT   8787
#define FDSIZE        1024
#define EPOLLEVENTS 20

static void handle_connection(int sockfd);

static void
handle_events(int epollfd, struct epoll_event *events, int num, int sockfd, char *buf);

static void do_read(int epollfd, int fd, int sockfd, char *buf);

static void do_read(int epollfd, int fd, int sockfd, char *buf);

static void do_write(int epollfd, int fd, int sockfd, char *buf);

static void add_event(int epollfd, int fd, int state);

static void delete_event(int epollfd, int fd, int state);

static void modify_event(int epollfd, int fd, int state);

int main(int argc, char *argv[]) {
    int sockfd;
    struct sockaddr_in servaddr;
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(SERV_PORT);
    inet_pton(AF_INET, IPADDRESS, &servaddr.sin_addr);
    connect(sockfd, (struct sockaddr *) &servaddr, sizeof(servaddr));
    //处理连接
    handle_connection(sockfd);
    close(sockfd);
    return 0;
}


static void handle_connection(int sockfd) {
    int epollfd;
    struct epoll_event events[EPOLLEVENTS];
    char buf[MAXSIZE];
    int ret;
    epollfd = epoll_create(FDSIZE);
    add_event(epollfd, STDIN_FILENO, EPOLLIN);
    for (;;) {
        ret = epoll_wait(epollfd, events, EPOLLEVENTS, -1);
        handle_events(epollfd, events, ret, sockfd, buf);
    }
    close(epollfd);
}

static void
handle_events(int epollfd, struct epoll_event *events, int num, int sockfd, char *buf) {
    int fd;
    int i;
    for (i = 0; i < num; i++) {
        fd = events[i].data.fd;
        if (events[i].events & EPOLLIN)
            do_read(epollfd, fd, sockfd, buf);
        else if (events[i].events & EPOLLOUT)
            do_write(epollfd, fd, sockfd, buf);
    }
}

static void do_read(int epollfd, int fd, int sockfd, char *buf) {
    int nread;
    nread = read(fd, buf, MAXSIZE);
    if (nread == -1) {
        perror("read error:");
        close(fd);
    } else if (nread == 0) {
        fprintf(stderr, "server close.\n");
        close(fd);
    } else {
        if (fd == STDIN_FILENO)
            add_event(epollfd, sockfd, EPOLLOUT);
        else {
            delete_event(epollfd, sockfd, EPOLLIN);
            add_event(epollfd, STDOUT_FILENO, EPOLLOUT);
        }
    }
}

static void do_write(int epollfd, int fd, int sockfd, char *buf) {
    int nwrite;
    nwrite = write(fd, buf, strlen(buf));
    if (nwrite == -1) {
        perror("write error:");
        close(fd);
    } else {
        if (fd == STDOUT_FILENO)
            delete_event(epollfd, fd, EPOLLOUT);
        else
            modify_event(epollfd, fd, EPOLLIN);
    }
    memset(buf, 0, MAXSIZE);
}

static void add_event(int epollfd, int fd, int state) {
    struct epoll_event ev;
    ev.events = state;
    ev.data.fd = fd;
    epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev);
}

static void delete_event(int epollfd, int fd, int state) {
    struct epoll_event ev;
    ev.events = state;
    ev.data.fd = fd;
    epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, &ev);
}

static void modify_event(int epollfd, int fd, int state) {
    struct epoll_event ev;
    ev.events = state;
    ev.data.fd = fd;
    epoll_ctl(epollfd, EPOLL_CTL_MOD, fd, &ev);
}